/*
 * Copyright (c) 2002-2018 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.doc.server.helpers;

import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Transaction;

public class Transactor
{

    private final UnitOfWork unitOfWork;
    private final GraphDatabaseService graphDb;
    private final int attempts; // how many times to try, if the transaction fails for some reason

    public Transactor( GraphDatabaseService graphDb, UnitOfWork unitOfWork )
    {
        this( graphDb, unitOfWork, 1 );
    }

    public Transactor( GraphDatabaseService graphDb, UnitOfWork unitOfWork, int attempts )
    {
        assert attempts > 0 : "The Transactor should make at least one attempt at running the transaction.";
        this.unitOfWork = unitOfWork;
        this.graphDb = graphDb;
        this.attempts = attempts;
    }

    public void execute()
    {
        for ( int attemptsLeft = attempts - 1; attemptsLeft >= 0; attemptsLeft-- )
        {
            try ( Transaction tx = graphDb.beginTx() )
            {
                unitOfWork.doWork();
                tx.success();
            }
            catch ( RuntimeException e )
            {
                if ( attemptsLeft == 0 )
                {
                    throw e;
                }
            }
        }
    }

}
